Cementitious spray applied fireproofing is not a new concept. For example, it is well known to spray apply fireproofing slurries to metal structural members and other building surfaces in order to provide a heat resistant coating thereon. U.S. Pat. Nos. 3,719,513 and 3,839,059, which are incorporated herein by reference, disclosed gypsum-based formulations that contain, in addition to the gypsum binder, a lightweight inorganic aggregate such as vermiculite, a fibrous substance such as cellulose, and an air entraining agent.
Furthermore, geopolymer types of cement, per se, are well-known. However, the use of geopolymer types of cement and concrete formulations in spray applied fireproofing is new. While Geopolymer types of cement have been studied extensively and it has been concluded that heat resistance is typically relatively high when compared to Portland cement, the challenges in using a Geopolymer type of cement in a density controlled, cold fusion mixture were both problematic and arduous.
As will be herein explained, the present inventors have solved these challenges, and reduced to practice a density controlled cold fusion concrete cementitious spray applied fireproofing.